1. Technical Field
The present invention relates to a method of manufacturing a piezoelectric device having a piezoelectric element including a first electrode, a piezoelectric layer, and a second electrode that are disposed on a diaphragm on a substrate.
2. Related Art
An ink jet recording head for ejecting an ink droplet is a typical example of a liquid ejecting head for ejecting a liquid droplet. For example, such an ink jet recording head includes a flow channel substrate that defines a pressure generating chamber in communication with a nozzle opening, and a piezoelectric actuator provided on one side of the flow channel substrate. The piezoelectric actuator is a piezoelectric element and changes the pressure of ink in the pressure generating chamber so that an ink droplet can be ejected from the nozzle opening.
The piezoelectric actuator includes individual electrodes separately provided for different active sections and a common electrode shared with the active sections. A piezoelectric layer is interposed between the individual electrode and the common electrode in the active section and not interposed between the individual electrode and the common electrode in an inactive section. In general, the active section is subjected to polarization treatment and polarized in one direction. In contrast, the inactive section is not polarized in one direction. JP-A-2006-174618, for example, describes a piezoelectric actuator where an active section and an inactive section are polarized in opposite directions.
As described above, in piezoelectric actuators in the related art, although an active section is polarized in one direction, an inactive section is unpolarized or polarized in a direction opposite to the polarization direction of the active section. Accordingly, a concentration of internal stress is caused at a boundary between the active section and the inactive section. The stress concentration may cause burning and cracking in the piezoelectric actuator, thus damaging the piezoelectric actuator.
Such problems are not unique to piezoelectric devices used for liquid ejecting heads, including ink jet recording heads, and may also be encountered with piezoelectric devices for other applications.